Use Import-Package instead of Require-Bundle for o.e.c.runtime to prevent importing unnecessary classes

[testforstephen]

What it does

Based on the discussion in eclipse-equinox/equinox#697 (comment), using Require-Bundle for org.eclipse.core.runtime will pull in all of org.eclipse.osgi which in-turn exposes you to all the JDK packages because this horrible re-export:

https://github.com/eclipse-platform/eclipse.platform/blob/6dd67323474b1b49d541bcd1e4ea8007ab2a36a4/runtime/bundles/org.eclipse.core.runtime/META-INF/MANIFEST.MF#L12C17-L12C87.

In our downstream project, we try to override some part of JRE packages within our fragment of org.eclipse.jdt.core. However, the default JDK packages always take precedence because of this Require-Bundle thing. The equinox team's recommendation is to use Import-Package instead of Require-Bundle for finer control over the imported classes.

How to test

This PR just minimizes the imported packages from the bundle o.e.c.runtime, without affecting the overall functionality of the feature.

[jukzi]

why importing an internal package?

[szarnekow]

Also why are these imported without a version constraint?

[testforstephen]

why importing an internal package?

The use of internal packages was not introduced by this PR; it originates from existing code in jdt.core, which already references these internal packages.

[mickaelistria]

Also why are these imported without a version constraint?

A version constraint was added in last revision of this PR.

[jukzi]

By arguing this PR affect your project you imply that the require-bundle silently is some public API. APIs should not be changed. I do not understand what exactly is going on there, but i have doubts that this is the right way to fix it.

[testforstephen]

By arguing this PR affect your project you imply that the require-bundle silently is some public API. APIs should not be changed. I do not understand what exactly is going on there, but i have doubts that this is the right way to fix it.

Both Import-Package and Require-Bundle are standard mechanisms for referencing packages from other bundles. And following https://docs.osgi.org/specification/osgi.core/7.0.0/framework.module.html#i3198951, Import-Package is even the preferred way for wiring bundles. Please clarify what issue do you see with this PR change.

[mickaelistria]

Based on discussion at eclipse-equinox/equinox#697 , it looks like we can add ;bundle-symbolic-name="org.eclipse.core.runtime";bundle-version="[3.29.0, 4.0)" to each Import-Package to keep some versioning.